Facile synthesis of trifluoromethyl covalent organic framework for the efficient microextraction of per-and polyfluorinated alkyl substances from milk products

J Chromatogr A. 2020 Jul 19;1623:461197. doi: 10.1016/j.chroma.2020.461197. Epub 2020 May 18.


Trifluoromethyl covalent organic framework (CF3-COF) is facilely synthesized at room temperature using for solid-phase microextraction (SPME). The CF3-COF coating displays an improved extraction performance for per- and polyfluorinated alkyl substances (PFASs) comparing to amorphous polymer coating, non-contained fluorine covalent organic framework coating and commercially available SPME coating. The fluorine affinity of trifluoromethyl in CF3-COF for PFASs is demonstrated using the density functional theory calculation. Following the microextraction with CF3-COF-coated fiber, the targeted PFASs are eluted with 1 mL acetonitrile and quantified by ultrahigh performance liquid chromatography tandem mass spectrometry. The low limits of detection are 0.1-0.7 pg g-1 for milk and 0.2-0.8 pg g-1 for milk powder, suggesting the outstanding sensitivity. The precision for the method ranges between 2.9 and 9.9%. The fiber-to-fiber repeatability is in the range of 4.2-9.5%. Under the optimum conditions, the relative recoveries are 91.0-110% with RSDs ≤ 10% for milk and 89.8-111% with RSDs ≤ 10% for milk powder.

Keywords: Covalent organic framework; Fluorine affinity; Per-and polyfluorinated alkyl substances; Room temperature; Solid-phase microextraction.

MeSH terms

  • Adsorption
  • Animals
  • Citrullus / chemistry
  • Fruit and Vegetable Juices / analysis
  • Glyoxal / chemistry
  • Hydrocarbons, Halogenated / isolation & purification*
  • Hydrogen-Ion Concentration
  • Metal-Organic Frameworks / chemical synthesis
  • Metal-Organic Frameworks / chemistry*
  • Milk / chemistry*
  • Phenols / chemistry
  • Reproducibility of Results
  • Resins, Synthetic / chemistry
  • Solid Phase Microextraction / methods*
  • Urea / chemistry


  • Hydrocarbons, Halogenated
  • Metal-Organic Frameworks
  • Phenols
  • Resins, Synthetic
  • Glyoxal
  • Urea